1. Field of the Invention
The present invention relates to a program product for data communication, a computer-readable recording medium in which a data communication program is recorded, a data communication apparatus, and a data communication method. Particularly, the present invention relates to a data communication program providing communication of firmware data via the Internet, a computer-readable recording medium in which the data communication program is recorded, a data communication apparatus, and a data communication method.
2. Description of the Related Art
The firmware controlling the operation of, for example, an image formation apparatus is conventionally written into a mask ROM (Read Only Memory). When the firmware has to be exchanged, the method is taken of replacing the mask ROM on the control board in the image formation apparatus with a mask ROM written with new firmware.
The exchange of a mask ROM is time-consuming and complicated. Therefore, a rewritable flash ROM is used instead of a mask ROM to improve the workability.
Methods set forth below have been taken to exchange the firmware written in a flash ROM.
As the first method, the method of using an external storage device such as a memory card is known. An I/F (interface) with an external storage device such as a memory card is provided in the image formation apparatus. A memory card with the new firmware is connected to that I/F. Then, the new firmware is written from the memory card to the flash ROM. In rewriting the firmware, remote operation is not possible in this method. There was the problem that the rewrite operation must be carried out actually at the site where the image formation apparatus is installed.
A method of utilizing a public switched network is known as the second method. This method is adapted to practical usage mainly in the field of facsimile apparatuses. Specifically, firmware is transmitted to an image formation apparatus from a remote apparatus connected to the public switched network. By downloading the transmission, the firmware is rewritten. Although there is no need to be actually present at the site as in the first method, the communication cost is high. Also, downloading the firmware is relatively time-consuming.
Reflecting the spread of the Internet, downloading the firmware through the Internet instead of through the public switched network is taken as the third method. The usage of the Internet allows reduction in the cost of transmission and the time required to download the firmware.
There are various protocols for communication through the Internet such as an HTTP (Hyper Text Transfer Protocol) to view a home page, an FTP (File Transfer Protocol) to transfer a file, an SMTP (Simple Mail Transfer Protocol) used in the communication of electronic mail, and the like. However, the protocol to download the firmware from a remote station to an image formation apparatus through the Internet is limited from the standpoint of security on the communication through the Internet. The protocol that can be used is rather limited.
Specifically, a firewall generally functioning as a “barrier” is provided at the connection of the Internet and each user to cope with illegal access and the like from the Internet into the user's internal system. The firewall has the capability to control the communication protocol that can be passed between the Internet and the internal system of the user. Accordingly, the passable protocol is limited. In general, the protocol of electronic mail is often set as passable. Therefore, the method of using an electronic mail system is conventionally employed in transmitting firmware via the Internet.
The size of the firmware in an image formation apparatus has now become as large as approximately 10 Mbytes in accordance with the high function and multi-feature thereof. It is expected that the size of the firmware will further increase in the future.
The mail server that collects electronic mail and provides distribution service generally has the size of the electronic mail that can be received restricted. The size of the electronic mail is often restricted to approximately 1 Mbytes.
In the case where firmware of the aforementioned size is to be transmitted through electronic mail, it is expected that rejection of receiving such large electronic mail will frequently occur since it exceeds the restricted size.
To avoid this, there is an approach of appropriately dividing firmware data and transmitting the same instead of transmitting the firmware data at one time. Specifically, the firmware that is to be transmitted is divided into a plurality of parts. The plurality of firmware is attached to separate electronic mail to be sequentially transmitted.
In the sequential transmission of the plurality of firmware for rewriting, there are cases where the rewriting order is determined. Therefore, the firmware is generally transmitted according to the desired order to be rewritten (written in).
However, even if the firmware is appropriately attached to electronic mail and transmitted in a divisional manner by the above-described method, there is a possibility that, during the firmware rewriting operation, the eventual order of the electronic mail received at the image formation apparatus side may differ from the transmitted order due to an error at the mail server side or by other causes.
If the firmware rewriting process is conducted in the received order at the image formation apparatus side in such a case, there is a possibility that the image formation apparatus having the firmware rewritten in an order differing from the proper order of the rewrite process corresponding to the transmitted order will not operate properly.
Furthermore, even if the transmitted order and received order are identical, partially rewriting the target firmware every time a divided firmware is received is not efficient. This is not an appropriate process even from the image formation apparatus side.